chore(tabs): remove undefined/unused token

[cdransf]

Description

Resolves stylelint violation by removing undefined and unused token

To-do list

• I have read the contribution guidelines.
• I have updated relevant storybook stories and templates.
• I have tested these changes in Windows High Contrast mode.
• If my change impacts other components, I have tested to make sure they don't break.
• If my change impacts documentation, I have updated the documentation accordingly.
• ✨ This pull request is ready to merge. ✨

[changeset-bot]

🦋 Changeset detected

Latest commit: e588c9e

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@spectrum-css/tabs	Patch

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[github-actions]

🚀 Deployed on https://pr-3315--spectrum-css.netlify.app

[github-actions]

File metrics

Summary

Total size: 4.30 MB^*
Total change (Δ): 🟢 ⬇ 0.13 KB (-0.00%)

Table reports on changes to a package's main file. Other changes can be found in the collapsed Details section below.

Package	Size	Δ
tabs	17.24 KB	🟢 ⬇ 0.04 KB

Details

tabs

Filename	Head	Compared to base
index-base.css	17.06 KB	🟢 ⬇ 0.04 KB (-0.24%)
index-theme.css	0.81 KB	-
index-vars.css	17.24 KB	🟢 ⬇ 0.04 KB (-0.24%)
index.css	17.24 KB	🟢 ⬇ 0.04 KB (-0.24%)
themes/express.css	0.72 KB	-
themes/spectrum.css	0.71 KB	-

* Size determined by adding together the size of the main file for all packages in the library.
* Results are not gzipped or minified.
* An ASCII character in UTF-8 is 8 bits or 1 byte.